Synthesis
GENERAL METHOD: Alkyl halide (or sulfate) (5 mmol) was heated at reflux with thiourea (0.381 g, 5 mmol) in ethanol (5 mL) for 1 hour. Upon completion of the reaction, the solvent was removed under vacuum and the residue was washed with ether (3 x 5 mL) to afford the corresponding S-alkyl isothiourea salt as a white solid in near quantitative yield. Without further purification, the resulting product was transferred to a three-necked round-bottomed flask equipped with a thermometer and a charging funnel and placed in an ice bath. Water (0.45 mL) and acetonitrile (10 mL) were then added. A solution of tert-butyl hypochlorite (2.86 mL) in acetonitrile (5 mL) was added slowly and dropwise to the mixture under vigorous stirring, controlling the reaction temperature in the range of 0-20°C. After the dropwise addition, the reaction mixture was continued to be stirred for 30 minutes. At the end of the reaction, the solvent was removed under vacuum, ether (15 mL) was added to dissolve the residue, the organic phase was washed with water (2 x 10 mL), dried over anhydrous sodium sulfate, and finally concentrated under vacuum to give high purity 4-methylbenzylsulfonyl chloride. The product can be further purified by petroleum ether-ethyl acetate mixed solvent recrystallization.
References
[1] Synthesis (Germany), 2015, vol. 47, # 20, p. 3186 - 3190
[2] European Journal of Organic Chemistry, 2012, # 26, p. 5028 - 5037,10
[3] European Journal of Organic Chemistry, 2012, # 26, p. 5028 - 5037
[4] Journal of the American Chemical Society, 1987, vol. 109, # 24, p. 7472 - 7477
[5] Synthesis (Germany), 2013, vol. 45, # 12, p. 1675 - 1682
